Background: Left bundle branch area pacing (LBBAP) has recently become a promising option for the near-natural restoration of electrical activation. However, the clinical relevance of therapeutic effects in individuals with heart failure with reduced ejection fraction (HFrEF) and dyssynchrony remains unknown. Methods & Results: MEDLINE, EMBASE, and Cochrane databases were searched from inception until June 2022. Data from each study was combined using a random-effects model, the generic inverse variance method of DerSimonian and Laird, to calculate standard mean differences and pooled incidence ratio, with 95% confidence intervals (CI). A total of 772 HFrEF patients were analyzed from 15 observational studies per protocol. The success rate of LBBAP implantation was 94.8% (95% CI 89.9 to 99.6, I2 = 79.4%), which was strongly correlated with shortening QRS duration after LBBAP implantation, with a mean difference of −48.10 msec (95% CI −60.16 to −36.05, I2 = 96.7%). Over a period of 6–12 months of follow-up, pacing parameters were stable over time. There were significant improvements in left ventricular ejection fraction (LVEF), left ventricular end-systolic volume (LVESV), left ventricular end-diastolic diameter (LVEDD), and left ventricular end-diastolic volume (LVEDV) with mean difference of 16.38% (95% CI 13.13 to 19.63 I2 = 90.2 %), −46.23 mL (95% CI −63.17 to −29.29, I2 = 86.82%), −7.21 mm (95% CI −9.71 to −4.71, I2 = 84.6%), and −44.52 mL (95% CI −64.40 to −24.64, I2 = 85.9 %), respectively . Conclusions: LBBAP was associated with improvements in both cardiac function and electrical synchrony. The benefits of LBBAP in individuals with HFrEF and dyssynchrony should be further validated by randomized studies.

Background: Recent randomized controlled trials (RCT) suggest that ablation is superior to antiarrhythmic drugs (AAD) as an initial therapy for paroxysmal atrial fibrillation (pAF) to prevent arrhythmia recurrences. We performed an updated meta-analysis of RCTs, to include recent data from cryoballoon-based ablation, and to compare arrhythmia-free survival and adverse events between ablation and AAMs. Methods: We searched MEDLINE and EMBASE from inception to December 2020. We included RCT comparing patients with pAF undergoing ablation or receiving AADs as an initial therapy. We combined data using the random-effects model to calculate hazards ratio (HR) for arrhythmia-free survival and odds ratio (OR) for adverse events. Results: Five studies from 2005-2020 involving 985 patients were included (495 patients and 490 patients underwent ablation and medication as initial therapy, respectively). Patients who underwent ablation had higher freedom from atrial tachyarrhythmias (AT) during the 12-24 months follow-up period (pooled HR=0.48, 95% CI:0.40-0.59, p<0.001) (Figure 2). In a subgroup analysis of ablation method used, both cryoablation group (pooled HR=0.49, 95% CI:0.38-0.64, p<0.001) (Figure 2A) and radiofrequency ablation group (pooled HR=0.47, 95%CI:0.35-0.64, p<0.001) (Figure 2B) showed reduction in AT recurrence compared to AAD group. There were no differences in adverse events including cerebrovascular accident, pericardial effusion or tamponade, pulmonary vein stenosis, acute coronary syndrome, deep vein thrombosis and pulmonary embolism, and bradycardia requiring a pacemaker. Conclusion: Catheter ablation (both cryoablation and radiofrequency ablation) is superior to AAD as an initial therapy for pAF in efficacy for reducing AT recurrences without a compromise in adverse events.